The Seismic Hazard Assessment for the Nuclear Power Plants Safety Laboratory (hereafter BERSSIN), whose activities and missions are presented in this paper is one of the four laboratories that composed the Waste Elimination and Geosphere service. The main assignment of the BERSSIN consists in the expertise of the safety demonstration of the nuclear operators from the seismic point of view, for new and old power plants. According to this task, the BERSSIN conducts research studies to improve seismic hazard assessment in France. Finally the division has to maintain the regulation for the nuclear power plant safety in coherence with the « state of the art ». The team is composed of three geologists, a seismotectonical specialist, five seismologists, a technical engineer and a technical assistant. At this time, three PhD and three postdoctoral students work in the team.